ayard RUSTIN is probably best remembered today for his close association with Martin Luther King Jr. and for his part in organizing the 1963 March on Washington.
But his role in the civil rights movement was only one of the many he played in his long and varied career. He was a major figure in the American pacifist movement and both a theorist and practitioner of nonviolence. He remained active
in peace causes until his death. He was, at various times, a Communist, an anti-Communist Socialist and a well-connected activist within the Democratic Party. He was a champion of the American labor movement and a well-traveled advocate
of human rights throughout the world. He was a talented musician who once considered a career as a professional singer and entertained audiences with his powerful tenor voice throughout his life. He was an avid collector of art and antiques.
He was a self-educated scholar of philosophy and political theory. He was a black American. And he was a gay man.

Rustin juggled these multiple roles and multiple identities with remarkable agility and, on the surface at least, seldom exhibited any serious anxiety about the strains they must often have created for him. Indeed, the picture that emerges from Jervis
Anderson's admiring portrait is of a man with an almost insouciant imperviousness to the many trials, assaults and frustrations he experienced as he moved through the public world. Rustin became an important force in many organizations
and movements, but in most of them he also alienated or embarrassed the leadership and found himself obliged to move on. His life was dominated by his consistent commitment to work actively on behalf of peace and social justice, but it
was also characterized by a restless instability. Few things could contain him for very long.

Mr. Anderson worked at the A. Philip Randolph Institute when Rustin was its executive director in the late 1960's, and he has been a staff writer at The New Yorker since 1968. ''Bayard Rustin: Troubles I've Seen'' reflects
both experiences: a reverence for Rustin that Mr. Anderson evidently derived from his association with him, and a clean, straightforward prose style characteristic of the magazine for which he works. He provides the first thorough account
of Rustin's life and career, and he suggests how Rustin became so eminent a figure without ever becoming a genuine leader. ''He didn't lead so much as he influenced,'' The New York Times observed in an editorial
when Rustin died in 1987. And he derived that influence from a combination of intelligence, magnetism and charm that Mr. Anderson effectively portrays.

Rustin was born in 1912 into a middle-class black family in West Chester, Pa. Not until he was an adolescent did he discover that the man and woman who had raised him were not his parents but his grandparents, and that his real mother was a woman he had
always assumed was his older sister, who had given birth to him when she was 17 years old. His father was a young man from the neighborhood whom Bayard never knew. As with many other important personal issues in Rustin's life, Mr.
Anderson offers few clues as to what effect this shocking discovery might have had on him. But he does note that Rustin went to some lengths to hide the facts of his birth from all but a few close friends.

The Rustins were Quakers, and Bayard grew up in and absorbed the political -- although never much of the religious -- ethos of his family's faith. He attended two colleges for a year each and, despite real academic gifts, left both under mysterious
circumstances, perhaps related to his homosexuality. Not long after that, he gave up his ambitions to become a professional musician, began his long career as a political activist and moved to New York, where he lived through most of the
rest of his life.

While taking courses at City College in the late 1930's, he became active in its Young Communist League, where he stood out as the only black person, as a talented organizer and as an epicure who introduced his comrades to good wines, cheeses and
pates. Rustin was interested in the league largely because of its commitment to the racial struggles in the South. In 1941, when Moscow ordered the American Communist Party to abandon its civil rights commitments and focus on World War
II, he left the organization.

He moved instead into the orbit of two great anti-Communist Socialists of the 1940's and 50's: A. Philip Randolph, the head of the Brotherhood of Sleeping Car Porters and one of the pre-eminent black leaders of the era; and A. J. Muste, a leading
pacifist and the head of the Fellowship of Reconciliation. Rustin helped Randolph organize a great march on Washington in the spring of 1941 -- and then angrily (if temporarily) broke with him when Randolph canceled the march in response
to Franklin D. Roosevelt's executive order banning racial discrimination in war industries. Rustin then joined forces with Muste and became a major figure in the Fellowship of Reconciliation's peace campaigns during and after
the war.

As a Quaker, Rustin easily won conscientious objector status. But true to the radical pacifism of Muste and his organization, he refused to report to the Civilian Public Service camp to which he was then assigned, because, he said, ''I cannot
voluntarily submit to an order stemming from the Selective Service Act.'' He spent nearly two and a half years in Federal prison as a result, the first of many imprisonments he experienced -- all but one of them for acts of conscience.

For the first eight years after the war, Rustin remained almost wholly within the Fellowship of Reconciliation and, as one of the organization's most popular and magnetic speakers, traveled widely on its behalf. But in 1953, while on a trip to California
sponsored by the organization, he was arrested on a morals charge when he was found having sex with two young men in a parked car near his hotel. Rustin's associates had long known of his homosexuality and had quietly tolerated it.
But the stern and at times self-righteous Muste could not forgive Rustin for a public scandal that might damage the fellowship, and he unceremoniously dismissed him from the organization.

It was a low point in Rustin's life -- and a moment that Mr. Anderson (who rarely offers much explanation of the critical ways in which Rustin's homosexuality surely affected him) handles gingerly. But Rustin's departure from the Fellowship
of Reconciliation in fact helped him move in new and more visible directions. Three years later, after working for a while for another pacifist organization (one more tolerant of his personal life), he responded to the urgings of the novelist
Lillian Smith and A. Philip Randolph and traveled to Montgomery, Ala., where he joined Martin Luther King Jr. in organizing the bus boycott that established King as a national figure. And for the next 10 years, he moved back and forth
between the world of the civil rights movement and the world of peace activism, both movements then committed to the Gandhian ideas of nonviolence to which Rustin subscribed. His past followed him everywhere -- his youthful ties to the
Communist Party, his wartime imprisonment, his arrest in California; Rustin often had to limit his public exposure to avoid discrediting King and others whom Southern white leaders (and the Federal Bureau of Investigation) were attempting
to destroy. But his training in the peace movement, and his sophisticated understanding of philosophies of nonviolence and social witness, made him an influential and valued adviser to more visible figures still searching for the intellectual
underpinnings of their efforts.

Rustin worked closely with King and the movement for nearly a decade and was particularly important in helping Randolph plan the 1963 March on Washington, the high-water mark of the nonviolent age of civil rights. But his relationship with King was never
an easy one. In part, it was because his radical past and very likely, although no one ever said so, his homosexuality made the beleaguered leaders of the Southern Christian Leadership Conference uncomfortable as they struggled against
the false accusations of Communism that the F.B.I. and others flung at them.

But Rustin's problems with King were also a result of Rustin's own relative conservatism in areas in which King was becoming more radical. He criticized King for denouncing the Vietnam War; Rustin opposed it too, but like many others he thought
King was compromising his leadership of the civil rights struggle by linking the issues. He opposed King's plan to take the movement to Chicago in 1966, warning (correctly) that the prospects for success were dim. And he began to
argue as early as 1967 that the ''movement'' phase of the civil rights struggle had lost its usefulness, that it was time for blacks to turn to politics (and to form coalitions with other progressive forces, most notably
labor) to work for the economic reforms that should now be their most important goal.

In the late 60's, Rustin at last found in his leadership of the A. Philip Randolph Institute the secure institutional base he had always lacked. But at the same time, he was becoming increasingly at odds with his former colleagues in the movement.
He was a strong critic of black nationalism and black power, a fervent believer in making political alliances with powerful groups dominated by whites, a defender of the Democratic Party and the labor movement, even an energetic supporter
of Albert Shanker and the United Federation of Teachers in their bitter battle against the effort by black activists to win community control of public schools in New York. He remained in demand as a speaker and adviser throughout the
70's and 80's, and he served on many committees and boards. But while his life was no less active in those years than it had been in his youth, his influence was less profound. And when he died, even his admirers had some difficulty
articulating exactly what had made him a significant figure in the nation's recent history.

But Rustin was a significant figure, perhaps more significant than Mr. Anderson's cautious biography makes clear. Not so much for the speeches he made, the organizations he assisted and the events he orchestrated, but for the way in which he, almost
alone among the major figures of the civil rights movement, tried to articulate a set of ideas and theories to justify their efforts and shape their tactics. He was a man of ideas and a man of action, of ''pragmatic idealism,''
as Vernon Jordan said in eulogy. And in an age of acrimony and division, he helped keep alive the fading vision of a broad, consensual coalition of the forces of change.

Alan Brinkley, a professor of history at Columbia University, is the author most recently of ''The End of Reform: New Deal Liberalism in Recession and War.''